Jayne Ness, M.D.-Ph.D. is a pediatric neurologist with a specific interest in neonatal brain injury. The candidate's intermediate aim is to define the cell death pathways that are important in neonatal hypoxia-ischemia (HI) with the long term goal of identifying neuroprotective agents with potential clinical utility. To achieve these goals, Dr. Ness will work with Drs. Kevin Roth, Steven Carroll and Michael Wyss at the University of Alabama at Birmingham. These mentors have extensive experience, respectively, in apoptosis in neurodevelopment, neurotrophic factors, and animal behavior paradigms. RESEARCH PROPOSAL: Perinatal HI injury is a common cause of neurologic disability mediated at least in part by Bcl-2 family dependent neuronal apoptosis. The Bcl-2 family consists of both pro- (Bax, Bad, Bid, Bim) and anti-apoptotic (Bcl-2, BcI-XL) proteins that regulate mitochondrial function, cytochrome c release and caspase activation. Bcl-2 family function is in turn, regulated by neurotrophic factor-induced phosphorylation and modulation of this pathway is an attractive therapeutic target for limiting the neuropathological consequences of perinatal brain injury. Previous studies have implicated Bax as an important mediator of neuronal cell death in several models of brain injury, including neonatal HI and I hypothesize that specific BH3 domain-only members of the Bcl-2 pro-apoptotic subfamily will regulate Bax-dependent neuronal cell death in the neonatal brain. Further, I hypothesize that the known (NGF, BDNF) or potential (neuregulin) neuroprotective effects of neurotrophic factors in neonatal HI brain injury are mediated through the regulated phosphorylation of BH3-only Bcl-2 family members. To test these hypotheses and delineate the molecular pathways of neonatal HI induced neuronal death, I will utilize wild-type and transgenic mice deficient in specific pro-apoptotic BH3-only proteins (Bad, Bim, Bid) and other apoptosis-associated proteins in two models of neuronal HI. First, whole animal studies of focal ischemia will directly assess the role of specific Bcl-2 family members and neurotrophic factors in regulating neonatal HI injury and second, in vitro studies of primary cortical neuron cultures will be used to help define the mechanisms by which specific gene disruptions and/or neurotrophic factors attenuate oxygen-glucose deprivation-induced death. These models utilizing gene-disrupted mice are unique tools that will facilitate a better understanding of the molecular mechanisms underlying neonatal HI brain injury and the identification of potential targets for therapeutic intervention.